Agronomic evaluation of a homogenous nitrogen-phosphorus-sulphur fertilizer in southern Manitoba
Bibliographic record
Abstract
Field studies and a growth chamber study were conducted to evaluate the effect of a homogeneous nitrogen-phosphorus-sulphur (NPS) fertilizer on the emergence and crop utilization of phosphorus (P) and sulphur (S). In the field study, spring wheat (Triticum aestivum L. cv. AC Barrie) and spring canola (Brassica napus L. cv. DKL 34-55) were grown in southern Manitoba and fertilized with NPS, monoammonium phosphate (MAP) + ammonium sulphate (AS), MAP + elemental S-bentonite (So), MAP only and a control (no P or S); and S was applied at 0,5, 10, 15 and 20 kg ha-1. Wheat and canola emergence was not affected by any of the seed-placed P and S fertilizer sources or S rates used in the study. The NPS and other P fertilizer sources increased dry matter yield 6 - 10% in wheat at midseason but not at maturity; canola yields were not increased by P and S fertilization at any stage. At midseason, all of the phosphate fertilizers increased P uptake by 8 - 13% in wheat and 23 - 45% in canola, while NPS and MAP + AS increased S uptake by wheat 7 - 9 %. At maturity, all of the P fertilizers increased total P uptake by 9 - 12% in wheat but not in canola, and all responses to S fertilization had disappeared. To determine the availability of P, SO4 and So in NPS fertilizer, two S-deficient soils were used for a growth chamber study. Spring canola was fertilized with NPS, MAP + AS, MAP + So, MAP only, AS only and a control (no P or S). At 45 days after emergence, the canola was harvested and dry matter yield, P and S uptake were measured. After this harvest, the soils were incubated to simulate potential So oxidation conditions between cropping seasons in Manitoba. The pots were then replanted to a second crop of canola to measure residual P and S supplied by NPS fertilizer. In the first canola crop, dry matter yield and apparent P fertilizer use efficiency of NPS fertilizer was 75% and 81% of that for MAP + AS respectively. The apparent S fertilizer use efficiency for NPS was 35% of that for MAP + AS. When the second crop was grown without P and S fertilization, dry matter and residual P and S uptake were highest for the NPS treatment; however, the cumulative dry matter yield (crop 1 + 2) produced with NPS fertilizer was 83% of that for MAP + AS. The apparent P fertilization efficiencies for MAP + AS and NPS fertilizers were 54 - 56% over the two cropping periods. However, the apparent S fertilizer use efficiency of NPS fertilizer was approximately 50% lower than MAP + AS. Overall, the studies indicated that NPS fertilizer was not detrimental to wheat and canola emergence at the rates used in the study; the availability of P from NPS fertilizer appeared to be at least equivalent to MAP; and that only the SO4-S portion of NPS fertilizer appeared to be available to crops, with no measurable amount of oxidation of the So-S portion.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".